William henry iiiggin



'llstrrsn STATES PATENT Fries PROCESSOF -MAKING SODIUM ACETATE.

SPECIFICATION forming part of Letters Patent No. 511,143, dated December19, 1893.

Application filed May 27, 1892. semis. 434.651.

(N0 specimens.) Patented in England August 8,1891, No. 18,409; in

Germany May 8, 1892, No. 69,786; in France May 9,1892,No.221,481; inBelgium May 9, 1892, No. 99,602, and in hustria Huugary May 11, I892,No. 24,840 and No. 37,915.

land, have invented certain new and useful Improvements in the Treatmentand Utilizatron oi Es'parto-Liquor and other SimilarAlka line Liquorsand By-Prodncts; and I do hereby declare the following to be a full,clear, and

exact description of the invention, which will enable others skilled inthe art to which it appertains to make and use the same, and for whichforeign patents have been obtained as follows: British, No. 13,409,dated August 8, 1891; French, No. 221,481, dated May 9, 1892; Belgian,No. 99,602, dated May 9, 1892; Austro-Hungarian, No. 2 1,840 and No.37,915, dated May 11, 1892, and German, No. 69,786, dated May 8, 1892.

My said invention relates generally to an improved method of treatingthe alkaline liquors which have been used to boil raw fibrous materialsfor use in paper making and other manufactures, such for example as thecaustic soda lye which has been used to boil espartograss, straw, woodor other fibrous materials for the purpose of obtaining the fibers in acondition suitable for paper making as is well understood.

The object of my invention is to obtain acetate of sodium from suchalkaline liquors and by-products and to recover part of the alkali usedin their preparation.

The ordinary method of treating alkaline liquors of the class describedconsists of evaporation of'the water and calculation of the'resi-v dueby the use of a high degree of temperature.

The essential feature of my invention consists in maintaining thetemperature so low that the acetate formed isnot decomposed.

The improved process is carried into effect by evaporating the watercontained in the solution and subjecting the residual mass obtainedthereby in any suitable apparatus to carefully regulated heat in such amanner that it is maintained at a temperature slightly below that atwhich acetate of sodium begins to decompose and which in the case of theresidue from esparto-liquor for example, would be about 400 centigrade.The mass is subjected to this heat until it ceases to give off stronglysmelling gases containing nitrogenous bases and other impurities, but noacetic acid which are evolved under this treatment. The subjection ofthe residual mass to this carefully regulated temperature is the chiefpoint in my improved process, because if the indicated temperatureshould be unduly exceeded the acetate of sodium present in the masswould be decomposed and lost while if too lowa temperature were employedthe acetate of sodium would be obtained in considerably less quantity.When properly conduced at or about the temperature I have indicated theresult of the process is that some of the or-. ganic matter is notdestroyed but remains combined with a proportion of soda in thecommercially valuable form of acetate of sodium. The mass is maintainedat the requisite temperature until the strongly smelling gases are nolonger given oft whereupon it may be Withdrawn. I have mentioned 400centigrade as a suitable temperature to use because the production ofacetate is practically complete at that temperature which isnevertheless still about 50 below the point at which decomposition ofthe acetate under these circu instances would take place whether theoperation is carried on-in a closed or open vessel. Another advantage ofthe high temperature is that the resulting mass or char produced at thatheat is of the most favorable nature for the extraction of the acetateand its subsequent refining by any well-known and acceptable method. Iwish however to state expressly that the application of any temperaturebelow the decomposing point of acetate and above 200 centigrade willresult in the production of acetate in large quantity in the massalthough as I have already stated the results will not be so good aswhere a temperature of about 400 centigrade is used as directed. Theresulting mass or char produced at the lower temperatures is also lessamenable to treatment for the recovery of the acetate than is the massor char obtained by the higher temperature. The said resulting char ormass, as obtained preferably from the higher temperature under the mostmproved method of carrying my'invention into elfect, consists of a dryeasily pulverized coke-like mass which contains frequently about fifteenper cent. of its own weight of anhydrous acetate of sodium. When treatedwith water in a suitable manner it yields the most of the containedacetate of sodium along with some carbonate of sodium and organic matteras a solution from which the sodium acetate maybe removed byfractionalcrystallization, or the solution may be otherwise utilized.There is also a quantity of black insoluble residue which after dryingmay be burned, when it leaves as a White ash a large proportion of thealkali (originally used in tha preparation of the liquor) as carbonateof so a.

In practice it will be found that dififerent liquors or by-productsrequire slightvariations in the temperatures at which my improvedprocess can be best carried out butin any oase-the-tem peratu re shouldalways be as nearly below the point at which the acetate decomposes asis safe, regard being had to the dangerof local or accidentaloverheating.

Too low a temperature is to be avoided because as I have explained notonly'is the acetate obtained less in quantity but also the mass is moresoluble in water and the acetate cannot therefore be so effectuallyseparated.

What I claim is- The improved method of treating espartoliquor and othersimilar alkaline liquors, solutions and by-products so as to obtainsolutions containing acetate of sodium therefrom, consisting inevaporating the water from such liquors or solutions, and treating theresidue by carefully regulated heat so that the temperature of theresidue shall exceed200 centigrade but shall never reach the heat atwhich sodium acetate is decomposed thereby producing a mass or charwhich upon treatment with water yields a solution of acetate of sodiumalong with other matters substantially as described and shown.

This specification signed and witnessed the 4th day of May, 1892.

v WILLIAM HENRY HIGGIN.

Witnesses:

JOSHUA EMPIRSLE, RICHARD IBBERSON.

